Spun Hub or gear/dog damage

[brichbk]

I have a 1979 70 HP Johnson on a 16ft Ranger Bass Boat.

A few weeks a go I was launching and managed to back into a shallow spot and while in reverse hit bottom (sand bottom). Since then moving the throttle in forward I would hear it trying to engage for a second then it would engage and be fine.

It was only intermittent the last few times I went out. Until today, I was out on a river for the first time and while motoring around at the slowest speed I came across a shallow point and again the prop hit bottom. I immediately shut down the engine, raised it up, and drifted through the shallow point. When I restarted the engine and tried to put it in forward it would make the noise like it's trying to engage but no forward movement. But this time it wouldn't engage.

When I push the throttle all the way forward (WOT) it will engage and I can back off and the boat will move forward. Once I move the throttle back to neutral and throttle forward again it makes the sound like it's trying to engage but the boat doesn't move. I heard a couple big clunks when it does this, but nothing different than it did before when it first moved into gear. It reminds me of when you put a car in neutral and step on the gas, the engine revs but nothing happens.

I was reading in a few threads and tried the spun hub test. I turned the key and moved the throttle forward. I then tried to turn the prop by hand it turns just less than 1/4 turn.

Do I need a new prop or are there gear/dog problems? Or does this sound like a whole different issue?

 

[kbait]

Re: Spun Hub or gear/dog damage

Use a marker to mark the propshaft and prop in-line. Run until it 'slips' and check marks. If they aren't aligned, spun prop hub. Do the test twice if they're still lined up, as it may have happened to slip to the same spot.

 

[brichbk]

Re: Spun Hub or gear/dog damage

Use a marker to mark the propshaft and prop in-line. Run until it 'slips' and check marks. If they aren't aligned, spun prop hub. Do the test twice if they're still lined up, as it may have happened to slip to the same spot.

"propshaft" would be what the nut is screwed onto -- correct?
"prop in-line" would be the inside of the prop -- correct

I would have to do this in the water. When I had it on the muffs I could not duplicate the problem.

 

[boobie]

Re: Spun Hub or gear/dog damage

You have to have it in the water under load to do this test.

 

[samo_ott]

Re: Spun Hub or gear/dog damage

It kinda of sounds like your shifter cable is out of alignment. I'd look into that also if they prop is not spun.

 

[5150abf]

Re: Spun Hub or gear/dog damage

Spun props don't clunk and it generally takes a good bit of power to get them to spin, I think your problem is inside the lower.

You really want to watch putting it in gear at anything above an idle, the gears are pretty brittle and the shock will cause them to fail.

If it is a rapid clicking noise it is the clutch dog trying to engage.

I would first try to adjust your shift cable, move the shifter into forward and watch which way it goes and adjust the cable a couple turns that way.

You need to watch because if you go too far you will lose reverse.

You may just need a new cable but watch using the engine till you get this fixxed or yu will trash the lower.

 

[ONERCBOATER]

Re: Spun Hub or gear/dog damage

just a note on spun hubs, from my exp a spun hub may seem perfectly fine when you look at it, it may also (with wires removed from plugs) with motor in gear easily have enough grab to turn engine over when you turn the prop by hand but still spin when the engine moves up in power and rpm......

i spent 3hrs figuring it out the 1st time i did it.

Sean

 

[brichbk]

Re: Spun Hub or gear/dog damage

So I got the boat to the launch to test for a spun hub and after two tests the hub was fine.

When I tested it both times it was the same problem with it "trying to engage" or catch. The second time I noticed that one of the parts was shaking significantly more than the others (see pic).

 

[brichbk]

Re: Spun Hub or gear/dog damage

If it is a rapid clicking noise it is the clutch dog trying to engage.

I would first try to adjust your shift cable, move the shifter into forward and watch which way it goes and adjust the cable a couple turns that way.

You may just need a new cable but watch using the engine till you get this fixxed or yu will trash the lower.

So it doesn't look like a spun hub and it sounds like maybe it's the clutch dog or the shift linkage.

I would first try to adjust your shift cable, move the shifter into forward and watch which way it goes and adjust the cable a couple turns that way.

In the picture I attached I believe the linkage that I said shakes alot is the one I need to adjust, but when I tried turning the black plastic part it didn't seem to do anything.

 

[samo_ott]

Re: Spun Hub or gear/dog damage

When you turned the black plastic adjusting screw did the screw move in and out or did it turn and not seem to make a difference with the engine shifting?

 

[5150abf]

Re: Spun Hub or gear/dog damage

You don't need to adjust it alot and make sure you are turnign it the right way, also a good idea to count the turns so you can put it back if it doesn't work.

I would really limit the time on the engine till you figure this out, the grinding you here is the dog grinding against the gear, it doesn't take alot of this to ruin the lower.

 

[brichbk]

Re: Spun Hub or gear/dog damage

When you turned the black plastic adjusting screw did the screw move in and out or did it turn and not seem to make a difference with the engine shifting?

I turned it less than a full turn and it didn't look like the screws moved at all.

 

[brichbk]

Re: Spun Hub or gear/dog damage

You don't need to adjust it alot and make sure you are turnign it the right way, also a good idea to count the turns so you can put it back if it doesn't work.

I would really limit the time on the engine till you figure this out, the grinding you here is the dog grinding against the gear, it doesn't take alot of this to ruin the lower.

Good idea, I will keep track of the turns and I don't plan on using the boat until this is fixed. It's almost time to winterize anyways.

 

[brichbk]

Re: Spun Hub or gear/dog damage

Problem fixed!!!

I adjusted the shift lever, dipped the boat in the lake, started the motor, shifted into forward and it sounded good, shifted into reverse and it sounded good. So I launched the boat and went out on the lake for further testing . Everything ran great!

Thanks for the help iboats community and especially you guys in this thread!

 

[samo_ott]

Re: Spun Hub or gear/dog damage

Yay!